Your cart
There are no more items in your cart
Example of designation :
H-screw, M8-50 - 8.8 (sometimes referred to as H-screw M8x50 8-8): Hexagon head screw (H), ISO thread (M) ) with coarse pitch, nominal diameter 8mm, length under head 50mm and quality class 8.8 (steel strength).
Designation in France
In technical communication in France, the standards NF E 25-xxx are used: NF E 25-112, NF E 25-116, NF E 25-125, ...
The designation starts with the word Vis (in French documents).
HEAD SHAPE SYMBOL
For several years now, mechanical engineering standards have not included a symbol for screw head shapes. Instead, the name of the screw head is indicated in words.
Example: Hollow hexagon socket head screw (chc), slotted pan head screw.
As a standard is not binding, many designers and draughtsmen use the symbols of the old standards:
Headless : A
Cylindrical : C
Milled : F
Drop of tallow : G
Hexagonale : H
Japy : J
Square : Q
Round : R
COMPLEMENTARY SHAPE SYMBOL
Curved : B
Curved Large : BL
Base : D
Centered baseplate : F
With slots : K
With collar : T
THREAD SYMBOL
Metric thread (ISO) : M
Sheet metal thread : ST
Wood threading : VB
Trapezoidal thread : TR
Round thread : RD
THREADED LENGTH (if any)
The threaded length is different.
EXTREMITY SYMBOL
Chamfered end : CH
Bulging toe : BB
Short nipple : TC
Long nipple : TL
Flat end : PL
Bowl end : CV
QUALITY CLASS
The quality class refers to the strength of the steel. According to ISO 898-1:May 2013 (ISO 898-1:1988) (replacing ISO/R 898-3:1969), the class is denoted by two integers n¹.n², for example. "5.6", "8.8" or "10.9" or "12.9".
The first number represents the breaking strength of the steel in MPa (or N/mm²)
Rm = n¹x100MPa
The second number represents the ratio of the yield strength Re to the tensile strength Rm:
Re =0.1xn²xRm
Re is 10xn² % of Rm
COATING ACCORDING TO OTHER STANDARDS
For anchor bolts, the international automotive standard SAE J429 is sometimes used to designate the quality class.
Steel properties according to SAE J429